By 2012 sensors such as microphones, cameras, GPS, accelerometers, and temperature and magnetic sensors will be common in most PCs, allowing Windows 8 to interact with the user's environment in new and interesting ways.

One scenario uses facial recognition software to verify a user's identity.

"Amish walks into his home office," Microsoft writes in one of many fictional scenarios outlined in the Windows 8 slide decks. "The proximity sensor on his PC detects motion, and wakes the PC. By the time Amish sits down, his PC is powered up. It scans his face and logs him in. Finally, when Amish gets up and leaves, his PC notices that he's gone and locks itself and powers down."

Windows 8 may also eliminate the need for remembering passwords across multiple websites.

"Password pain has reached a tipping point," Microsoft says. "Windows 8 could include a way to securely store usernames and passwords, simplifying the online experience."